Researchers Say Head-mounted Haptics Can Combat Smooth Locomotion Discomfort in VR

Researchers from the National Taiwan University, National Chengchi University, and Texas A&M University say that haptic feedback delivered to the head right from a VR headset can significantly reduce discomfort related to smooth locomotion in VR.

Moving players artificially through large virtual environments isn’t a trivial task. While there’s many different ways to move around in VR, smooth locomotion—the kind you’d find in most first-person non-VR games—is a popular method because it maps easily to existing game design paradigms. Unfortunately this method of virtual locomotion isn’t comfortable for everyone.

In a paper published as part of CHI 2020—a conference focused on human-computer interaction—researchers describe their WalkingVibe system which uses simple head-mounted haptics to provide sensations that synchronize with the movement of the user in virtual reality. After conducting an initial study with 240 participants, the researchers say the system can significantly reduce discomfort associated with smooth locomotion and even improve immersion.

Using the Vive Pro Eye headset as the foundation for their work, the researchers tested two different types of head-mounted haptics: vibrating motors and actuated tappers (literally little arms that can gently tap the side of the user’s head). The haptics were synchronized to virtual footsteps to offer a stand-in stimulus for the sensations associated with real walking.

The researchers built a test VR application in Unity, which was linked to the haptics, in which users were walked through three different VR environments and asked to rate their level of comfort.

To check their work, the researchers also ran the same tests with both visual and auditory stimulation (artificial head bobbing and footstep sounds) without any haptics to isolate any effect. They also ran tests with randomized haptic stimulation to tell if the synchronization of the stimulation mattered to the outcome.

The results from the 240 participant study show a significant improvement in comfort and an improvement in realism from the haptics compared to the other methods tested.

[…] all 2-sided tactile designs significantly reduced VR sickness compared to the conditions with no haptic feedback. In addition, WalkingVibe with the 2-sided, footstep-synchronized vibrotactile cues significantly reduced discomfort compared to all other conditions and significantly improved realism compared to all tactile conditions, including tapping-based feedback.

The researchers also discussed the limitations of their experiments. Notably, users in this study were physically seated; the same tests were not conducted with physically standing users. Many VR games with artificial locomotion accommodate seated and standing players. Furthermore the researchers said that the artificial movement during the tests was not under the control of the test subjects; they were essentially taken along a guided path without active control over their movement.

The full paper is titled WalkingVibe: Reducing Virtual Reality Sickness and Improving Realism while Walking in VR using Unobtrusive Head-mounted Vibrotactile Feedback, and credits researchers Yi-Hao Peng, Carolyn Yu, Shi-Hong Liu, Chung-Wei Wang, Paul Taele, Neng-Hao Yu, and Mike Y. Chen.